The Cassini orbiter returned some of the most stunning images ever taken of Dione, one of the dozens of satellites of Saturn. The flyby took place on June 16, as the spacecraft passed within just 321 miles of the icy body.
Dione has a diameter of roughly 700 miles, so traveling around the globe in a specially-designed car would be about the same distance as driving between San Francisco and Chicago. This body ranks as the 15th largest satellite in the Solar System.
"On Aug. 17, the spacecraft will make its final flyby of Dione, diving to within 295 miles (474 kilometers) of the surface. The final Dione encounter will be Cassini's second-closest brush with the icy moon. A December 2011 flyby saw the spacecraft reach an altitude of just 60 miles (100 kilometers) above Dione," NASA officials wrote on the mission Web site.
This Saturnian moon was discovered in 1684 by the Italian astronomer Giovanni Domenico Cassini, using an aerial telescope at the Paris Observatory. This odd design of telescope dose not use a tube at all - just a lens and eyepiece, tied together with a string. This Saturnian satellite is named after the Greek Titaness Dione.
Cassini was launched from Earth on October 15, 1997, and entered orbit around Saturn on July 1, 2004. Since then, the robotic observatory has orbited around the planet, studying the moons and rings of the gas giant. The spacecraft was launched with a companion, the Huygens lander, which touched down on the surface of the giant moon Titan, becoming the first vehicle to touch the surface of a body in the outer Solar System. Huygens communicated data back to Earth using Cassini as a relay station, connecting to controllers back on the ground.
During the flyby, Cassini observed a region called Eurotas Chasmata, which was first seen by astronomers during the Voyager missions.
"After the Voyager encounter, scientists considered the possibility that the streaks were bright material extruded onto the surface by geologic activity, such as ice volcanoes. Cassini's close flybys and sharp vision later revealed the bright streaks to be an intricate network of braided canyons with bright walls, called linea," Cassini program managers reported.
Late in 2015, the Cassini will leave the equatorial plane of Saturn, where most of more than 60 moons orbits the giant planet. Then, the spacecraft will race between the innermost ring of Saturn and the gas giant. This daring move holds significant risks for the vehicle, and is only being undertaken as the 18-year-old spacecraft is nearing the end of its operational life.
